Ball-caster.



No. 666,009. Patented Jan. l5, l90l. M. C. HALL.

BALL EASTER. (Application filed Sept. 12, 1900.)

(Ne Model.)

STATES MILTON O. HALL, OF BAKERSFIELD, CALIFORNIA.

BALL-CASTER.

SPECIFICATIQN forming part of Letters Patent No. 666,009, dated January15, 1901.

Application filed September 12, 1900. derial No. 29,740- (No model.)

To all whom it may concern:

Be it known that I, MILTON C. HALL, a citizen of the United Stat es,residing at Bakersfield, county of Kern, State of California,haveinvented an Improvement in Ball-Casters; and Thereby declare thefollowing to be a full, clear, and exact description of the same.

My invention relates to improvements in that class of furniture and likecasters in which a large ball is adapted to form contact with the flooror other surface and is itself contained within an exterior casing,within which are smaller balls which form abearing for the larger one.

My invention consists of an exterior cylindrical casing adapted tocontain the larger ball in its outer end and having means for fixing itto the article which is to be carried by the casters and an interiorportion of small diameter and a ball-bearing ring, between which andsaid inner cylinder a peripheral row of balls is arranged to bear uponthe sides of the larger ball. Within this bearing-ring and at the bottomof'the inner casing is a concaved steel bearing-plate, upon whichanother set of balls is adapted to roll in such relative relation to theperipheral set that they form a separate bearing for the base or innerconvexity of the large ball.

My invention also comprises details of construction, which will be morefully described by reference to the accompanying drawings, in which-Figure l is a vertical section through the caster. Fig. 2 shows theapplication to a trunk. Fig. 3 shows the caster held in position by anextra flange.

The casing A is made of sufficient interior diameter to receive thelarge ball 2 and allow it to turn freely therein. The outer end of thiscasing A is contracted, so that the contracted portion extending beyondthe plane of the center of the sphere is sufficiently smaller than thediameter thereof to prevent the latter from falling out. The inner endof the casing is in the form of a cup 3, which may be formed integralwith the casing; but I prefer to make it as a separate structure inorder to allow the ball 2 to be properly seated and afterward to fit theouter casing A over it when the other parts are in place.

Within the cup 3 is a ring 4, the outer periphery of which is preferablymade convex or of such equivalent surface that a row of small balls a,resting upon this surface and against the inner surface of the cup, willhave two points of bearing-contact, one upon the outer periphery of thering and the other against the inner sides of the cup, so that theseballs will roll freely. Upon these balls the larger sphere 2 rests, thebearing being around the circumference of the ball in a plane at somedistance from its inner pole.

By the expression pole I mean an axial line through the ball which iscoincident with the axial line of the exterior cylindrical casing.

At the bottom of the cup and interior to the ring 4 is a bearing-plate6, upon which are placed one or more balls '7, upon which that portionof the ball surrounding the inner pole has a hearing. This plate 6 ispreferably made cup-shaped, so that the small balls 7 upon the cup willfit themselves to the periphery of the larger sphere, which thus has abearing, first, upon these balls on the plate, and, secondly, upon thering of balls previously described. These numerous points of bearing indifferent planes give great steadiness to the sphere and a perfectfreedom of movement when it rests upon a surface over which it is to bemoved.

. The plate 6 is fitted either into a countersink or groove made aroundthe inner part of the ring 4, or it may, if desired, be fitted to theinterior diameter of the ring, the object being in either case to holdit in proper position, but to allow it to be removed and replaced atwill. The ring is also made to removably fit within the cup, and allparts can thus be removed, inspected, and replaced at will. The cup fitsinto the interior of the inner end of the casing A and may, if desired,be slightly tapered, so that after the balls and their bearings havebeen put in position and the larger sphere placed upon them the outercasing can be pressed or driven down upon the outside of the cup and thewhole structure thus secured together. The inner end of the cup is theninserted into the article to which the caster is to be applied, and thewhole device is secured thereto by means of a flange 8 or equivalentlugs or fastenings.

If the casters are to be used for trunks, the

the outer end of the casing that but a small portion of the latter willproject, and the device will be less liable to damage from roughhandling to which trunks are exposed.

If desired, a supplemental flange 9 may be fitted loosely around thecasing, and this flange servesto secure the casing in place; but thecasing is loose enough to be freely turnable within the flange and thesocket into which it fits.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

l. The combination in a-ball-caster, of the exterior casing having theouter end contracted, a cup fitting the interior and of the casing, abearing-ring inclosed within the bottom of the cup and having an outerperipheral surface between which and the inner periphery of the cup,bearing-balls are disposed, a bearing-plate at the bottom of the cup andinterior to the ring, a second set of balls located thereon interior tothe ring, and a sphere inclosed within the casing and supporting the twosets of balls.

2. The combination in a ball-caster, of an exterior casing having acontracted outer end, a cup fitting theinner end of said casingaxiwithin the cup and having a convexed outer periphery, a series ofballs located between said couvexed periphery of the ring and the innersurface of the cup, aconcaved bearingplate located within the ring and asecond set of balls thereon and interior to the firstnamed balls, and asphere within the contracted end of the casing and supporting the twosets of balls.

3. The combination in a ball-bearing caster of an exterior casing havinga contracted outer end, within which the large ball is retained, meansfor attaching said casing to the article to be supported by the caster,a cup removably fitting the inner end of the casing and axially in linetherewith, a removable ringhaving aconvex outer periphery between whichand the inner surface of the cup a series of bearing-balls is disposed,a concaved removable bearing-plate fitting within the ring, and aplurality of balls carried upon said plate whereby two points of bearingin dififerent planes are provided, and a large ball or sphere protrudingfrom the casing and supporting the two sets of bearing-balls.

In witness whereof I have hereunto set my hand.

MILTON O. HALL.

